Lightning-arrester.



A. J. WURTS.

LIGHTNING ARRESTER. APPLIOATION FILED AUG. 2, 1905.

Patented Aug. 5, 1913.

O O 15 0 0 0 045 1 12 i /3 7'55 8 WITNESSES: INVENTOR UNITED STATES.PATENT OFFICE.

ALEXANDER JAY WURTS, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTING-HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

and State of Pennsylvania, have invented a new and useful Improvement inLightning- Arresters, of which the following is a specification.

My invention relates to li htning arresters for the protecting ofelectric circuits and it has "for its object to provide an improveddevice of the character and for the purpose indicated.

Among the various forms of lightningarresters which have beenconstructed is one.

which comprises a pair of horn-shaped or slender curved terminal pieces,that are so disposed with reference to each other as to provide a narrowair gap between two corresponding ends thereof and so that the remainingportions diverge. The occurrence of a static charge upon a circuit whichis protected by means of such a device is the cause of a dischargeacross the narrow air gap between the terminals, and if an are due tothe current in the main circuit follows the discharge, it will traveltoward the most widely separated ends ofthe terminal pieces and willrupture itself by reason of the greater length of the gap. In the use ofsuch devices the arcs which are formed between the terminals arefrequently of sufiicient duration to permit of surgings of the staticcharge in the circuit, which cause abnormal strains upon theinsulationof the circuit.

In order -to prevent the continuation of such arcs, I provide for theintroduction of a resistancein series with the are after the passage ofthe disru tive dischar e, and to this end I preferab y construct t oseortions of the terminal pieces between w ich the discharge first occursof low resistance material, and introduce comparatively high resistanceintothe diverging portions.

In one form of my device the diverging extended portions of the terminalpieces comprise a plurality of conducting ieces that are insulated fromeach other an that are arranged with air is aces between them. Inanother form the iverging extensions.

1 me be constructed of higher resistance ma;

1' terial than the portions which are separated by the smallest airspace. Thus when an aredue to the current in the main circuit fol-Specification of Letters Patent.

LIGHTNING-ARBESTEB.

lows a disruptive static discharge across the air space between theterminals and moves toward the diverging ends of the terminals, 1tencounters greater resistance and ruptures more quickly and surelythanwould otherwise be the case.

Figure 1 of the accompanying drawing is a diagrammatic view of a systemembodying my invention and Fig. 2 is a similar view of a systemembodying a modification thereof.

An electric circuit which it is desired to M protect from thedestructive effects ofstatic discharges,-- comprises distributingconductors 1 and 2 that'are supplied with electrical energy from anysuitable source,'such as a generator 3, and a protective circuit 4 forthe main circuit comprises a lightning .arrester 5, that is connectedbetween conductor 2 and the ground 6. The lightning ,arrester5.comprises a pair of horn-shaped or slender curved terminal pieces 7and 8 which are ararnged so that corresponding I Patented Aug. 5, 1913.Application filed August 2, 1905. Serial No. 272,401.

ends 9 and 10 thereof are adjacent to each other with a narrow air space11 between them, and so that the remaining portions 12 and 13 thereofdiverge from each other. The terminal pieces 7and 8 are preferablycomposed of non-arcing metal or other conducting material that is notreadily decomposed upon the occurrence of arcs between the terminals.Extensions 14 and 15 for the terminal pieces 7 and 8 comprise two setsof conducting pieces 16 that are separated from each other by air spaces17 and that are otherwise suitably insulated from each other. The pieces16 may also be composed of non-arcing metal or similar material.

If the main circuit becomes charged by lightning-or otherwise adischarge will occur-between the ends 9 and 10 of terminals 7 and 8 and,if an arc is produced, it will travel from the ends 9 and 10 of theterminals 7 and S'toWa-rd the opposite ends and will continue to traveltoward the outer ends of the extensions- 14 and'15 until it becomes soattenuated that it breaks. The

cause undue strains upon the insulation.

miv

In Fig. 2 extensions 18 and 19 of the terminals 20 and 21 are composedof any suitable high resistance material such as a mixture of clay andgraphite or carbon, and the resistances oi. the extensions may be madeuniform, or they may be caused to increase as the distance from thelower resistance portions of the terminals 20 and 21 illcreases, sothat, as the arc travels from the narrow portion of the air space to thewider portion, the resistance included in series circuit therewith israpidly increased. The operation of the lightning arrester of Fig. 2 isthe same as that of the form shown in Fig. 1.

An extremely important feature of myinvention is that resistance 'isintroduced into the discharge circuit only after the passage of adisruptive discharge through the circuit, and is not connectedpermanently in series with the lightning arrester air space, as has beendone previously, thereby oiiering resistance, to the disruptive discharge.

Other means than those here specifically shown and described forintroducing resistance into the circuit of a disruptive dischargemay beemployed, and the construction and arrangement of the circuits anddevices here shown may be varied considerably without departing from thespirit of my invention.

I claim as my invention: I

1. A lightning arrester comprising diverging terminal pieces oflowresistance and high resistance extensions for said terminal pieces.

2. A lightning arrester comprising diverging, discharge terminals, themost widely separated portions of which are of higher resistance thanthe remaining portions.

3. A lightning arrester comprising stationary diverging dischargeterminals and high resistance extensions.

4:. The combination with electric circuit conductors, of a lightningarrester which affords circuit connections between the same Copies ofthis patent may be obtained for after the occurrence land the ground andcomprises terminal n pieces separated by an air space and diverg' andstationary means for automatically increasing the resistance of thecircuit between the discharge terminals immediately after the occurrenceof an initial discharge.

6. A lightning arrester of the horn type in which one at least of thediverging electrodes consists of refractory material of relatively highspecific resistance.

'7. A lightning arrester'comprising electrodes of refractory material ofhigh resistance, sa'id electrodes being placed in proximity to oneanother and diverging from one another to expand an are fo medtherebetween.

8. A lightning arrester having electrodes in proximity to each other toform an air gap across which an abnormal current may pass, saidelectrodes being disposed to produce a progressive movement of said areand having a specific resistance suilicient to produce a. markedincrease in the resistance of the path traversed by the arcing current.

9. A lightning arrester having diverging carborundum electrodesseparated by an air gap, means for connecting one of said electrodes tothe line to be protected, and means for connecting the other electrodeto ground.

10. A lightning arrester consisting of a plurality of horn shapedrefractory electrodes having a relatively high specific resistance andseparated by an air gap across which an abnormal potential may,establish an arc. v i

In testimony whereof, I have hereunto subscribed my name this 28th dayof July,

ALEXANDER JAY VVURTS. Witnesses:

OTTO S. SCHAIRER, BIRNEY HINES.

five cents each, by addressing the Commissioner of Patents, Washington,1). c2-

